The jointer was a tool for shaping the mortar joint between bricks. A thin piece of steel bent into a curve or an S-shape or a V-shape. The mason ran the jointer along the fresh mortar and the jointer pressed the mortar into the shape the mason wanted. The shape of the joint determined how the wall shed water. The concave joint shed water. The flush joint held water. The raked joint collected water. The jointer was a water management tool disguised as a finishing tool.

The concave joint was the standard. The jointer was a half-round steel rod bent at a right angle so the mason could push it along the joint. The rod compressed the mortar into a concave channel. The channel was a tiny gutter between every brick. Thousands of tiny gutters covering the face of the wall. The rain hit the wall and ran down the tiny gutters and the gutters directed the water down and out. The wall was a drainage system made of gutters so small you could not see them from ten feet away.

The V-joint was formal. The V-jointer pressed a sharp groove into the center of the mortar joint and the groove cast a shadow and the shadow made the wall look like it was made of individual bricks. Without the shadow the wall looked like a single surface. With the shadow the wall looked like a stack. The shadow was the joint announcing itself. The concave joint whispered. The V-joint spoke. The raked joint shouted. The depth of the rake determined the volume.

The jointer was used when the mortar was thumbprint hard. Not wet. Not dry. Thumbprint hard. You pressed your thumb into the mortar and if the mortar held the print without sticking to your thumb the mortar was ready. The timing was everything. Joint too early and the mortar smeared. Joint too late and the mortar crumbled. The window was about thirty minutes depending on the temperature and the humidity. The mason read the weather through the mortar. The mortar was a thermometer and a hygrometer and a clock.

Nobody hand-joints every brick anymore on production masonry. The mortar gun extrudes a bead of mortar into the joint and the bead is already shaped. The gun replaces the trowel and the jointer in one motion. The gun is faster. The jointer was slower. The gun produces a consistent joint. The jointer produced a joint that varied slightly from brick to brick because the mason hand pressure varied slightly from stroke to stroke. The variation was the humanity. The consistency is the machine. A wall jointed by hand has rhythm. A wall jointed by gun has tempo. Rhythm breathes. Tempo counts.

See also: Trowel, Tuckpointing